Zobrazeno 1 - 10
of 239
pro vyhledávání: '"Brambilla, Maria"'
In this paper we study the birational geometry of $X$, a projective space $\mathbb{P}^n$ blown up at $s$ general points. We obtain a characterization of a special class of subvarieties, which we call Weyl $r$-planes, each of them being swept out by o
Externí odkaz:
http://arxiv.org/abs/2410.18008
The Terracini locus $\mathbb{T}(n, d; x)$ is the locus of all finite subsets $S \subset \mathbb{P}^n$ of cardinality $x$ such that $\langle S \rangle = \mathbb{P}^n$, $h^0(\mathcal{I}_{2S}(d)) > 0$, and $h^1(\mathcal{I}_{2S}(d)) > 0$. The celebrated
Externí odkaz:
http://arxiv.org/abs/2407.18751
We prove that Segre-Veronese varieties are never secant defective if each degree is at least three. The proof is by induction on the number of factors, degree and dimension. As a corollary, we give an almost optimal non-defectivity result for Segre-V
Externí odkaz:
http://arxiv.org/abs/2406.20057
Let $\overline{\mathrm{Mov}}^k(X)$ be the closure of the cone $\mathrm{Mov}^k(X)$ generated by classes of effective divisors on a projective variety $X$ with stable base locus of codimension at least $k+1$. We propose a generalized version of the Log
Externí odkaz:
http://arxiv.org/abs/2405.14553
Publikováno v:
Rendiconti del Circolo Matematico di Palermo, II. Ser 73(2024) 2195-2204
We study minimally Terracini finite sets of points in the projective plane and we prove that the sequence of the cardinalities of minimally Terracini sets can have any number of gaps for degree great enough.
Comment: To appear in Rendiconti del
Comment: To appear in Rendiconti del
Externí odkaz:
http://arxiv.org/abs/2401.17930
Publikováno v:
Rend. Lincei Mat. Appl. 35 (2024), 175-213
We characterize the number of points for which there exist non-empty Terracini sets of points in $\mathbb{P}^n$. Then we study minimally Terracini finite sets of points in $\mathbb{P}^n$ and we obtain a complete description in the case of $\mathbb{P}
Externí odkaz:
http://arxiv.org/abs/2306.07161
Our goal is twofold. On one hand we show that the cones of divisors ample in codimension $k$ on a Mori dream space are rational polyhedral. On the other hand we study the duality between such cones and the cones of $k$-moving curves by means of the M
Externí odkaz:
http://arxiv.org/abs/2305.18536
Publikováno v:
New York Journal of Mathematics, Volume 29 (2023), pp 1117 - 1148
We study surfaces of bidegree (1,d) contained in the flag threefold in relation to the twistor projection. In particular, we focus on the number and the arrangement of twistor fibers contained in such surfaces. First, we prove that there is no irredu
Externí odkaz:
http://arxiv.org/abs/2301.04874
Publikováno v:
Mediterr. J. Math. 19, 281 (2022)
We study smooth integral curves of bidegree $(1,1)$, called \textit{smooth conics}, in the flag threefold $\mathbb{F}$. The study is motivated by the fact that the family of smooth conics contains the set of fibers of the twistor projection $\mathbb{
Externí odkaz:
http://arxiv.org/abs/2204.10544
Publikováno v:
Math. Z. 303, 24 (2023)
A study is made of algebraic curves and surfaces in the flag manifold $\mathbb{F}=SU(3)/T^2$, and their configuration relative to the twistor projection $\pi$ from $\mathbb{F}$ to the complex projective plane $\mathbb{CP}^2$, defined with the help of
Externí odkaz:
http://arxiv.org/abs/2112.11100